Trying to attach an image to write-on drawing

Trying to attach an image to write-on drawing
by Benjamin Arthur on Jun 6, 2010 at 3:47:05 pm

This seems like it would be easy - I have a pencil picture and I just want it to follow the brush's write on effect. I have a simple picture that I drew in after effects I've tried copying the path and applying it to the pencil, but it doesn't follow the timing of my drawing. I've also tried attaching the expression pickwhip from the position of the pencil to the brush position, but the brush position never changes.

---------------------------------------------------------------------------------------------------------
Todd Kopriva, Adobe Systems Incorporated
putting the 'T' back in 'RTFM' : After Effects Help on the Web
---------------------------------------------------------------------------------------------------------
If a page of After Effects Help answers your question, please consider rating it. If you have a tip, technique, or link to share---or if there is something that you'd like to see added or improved---please leave a comment.

In this he's attaching the image to a mask, rather than an actual written write-on effect - I want my image to follow the timing of my wacom strokes like the brush does within after effects - not just the path.

from Write-on effect":
"A convenient way to animate Brush Position is to use Motion Sketch to create Position keyframes on a new solid layer and then use an expression on the Brush Position property to link it to the Position property on the new solid layer."

See the attached project. The black solid could be replaced with your pencil picture. The position keyframes were created with Motion Sketch.

---------------------------------------------------------------------------------------------------------
Todd Kopriva, Adobe Systems Incorporated
putting the 'T' back in 'RTFM' : After Effects Help on the Web
---------------------------------------------------------------------------------------------------------
If a page of After Effects Help answers your question, please consider rating it. If you have a tip, technique, or link to share---or if there is something that you'd like to see added or improved---please leave a comment.

Ahh, very cool, thank you Todd. It still seems odd that there is no way to do this directly, as drawing in the motion sketch makes drawing difficult and eliminates the ability to control brush size via the wacom tablet. I'm settling for a version of Aharon's tutorial, revealing the drawing I did in after effects using a reversed eraser effect to try to replicate the hand-drawn timing. Thanks again for the help.

What I'm looking for is a way to link the paint write-on directly to an image (pencil) so that whatever I paint gets linked to the tip of the pencil, following the speed and timing of the real-time drawing.

Paint's Brush doesn't have X,Y position information. Neither is there in its other properties.

Your best bet is to draw a mask and then copy the mask shape into Write-On's Brush Position - which has XY position information. Upon pasting, the time-spread of the keyframes pasted will be exactly 2 seconds. Timestretch the keyframes to suit your needs.

The data pasted on the Brush Position can be used as a source for a pick-whip action going from the Transform>Position property of the target, which is the pencil and linking it to the source property, Write-On's Brush Position property.

After the pick-whip, the pencil should be following the path. If the pencil doesn't then t is likely that your layers are not of a similar resolution. Ensure that all the layers share the same resolution. You may have to precomp layers to get this done.

Adjusting the Anchor Point of the pencil layer and changing its rotation may help, especially if it has been set to be a 3D layer, to take advantage of X and Y rotation features.

HTH
Roland Kahlenberg

Sell your AEPs with broadcastGEMs' DVD series of templates. Click here for more

So there's no real way other than manually to link an image up to the write-on's timing. That's surprising, I thought I was missing something obvious, I thought it would be a simple link to the speed/duration or something.